For decades, automobiles have had clocks installed on the dashboard. However, many of these dashboard clocks are inaccurate, losing or gaining time. The dashboard clock also becomes inaccurate when the prevailing time changes (i.e. from daylight savings time to standard time or vice versa). Furthermore, cars are mobile. Thus, driving the car into a different time zone causes the dashboard clock to be off by an hour.
The manual interface for resetting clocks in automobiles, however, can be very difficult, because this manual interface is usually very primitive. For example, the manual interface may only have three buttons: one to reset the time to 12:00, one to advance the hours, and one to advance the minutes. Because of this limited interface, it becomes very cumbersome, for example, to reset the dashboard clock when the dashboard clock happens to be five minutes too fast. In this case, the user has to push the advance-minute button 55 times, or hold it down for quite some time until the advancing minutes wrap around to the correct value. As another example, the first Sunday morning when the prevailing time changes from daylight savings time to standard time requires 11 pushes of the advance-hours button.
Various attempts have been made to provide a system for updating automobile clocks; however, these attempts have often proved impractical due to economic and regulatory constraints. For example, U.S. Pat. No. 5,805,530 to Youngberg discloses a device for communicating the time of day and other information to clocks in various appliances by various instrumentalities, such as an AC mains links for a television. For automobiles, Youngberg indicates that a radio frequency link can be provided from the master clock to the car. A difficulty encountered with the Youngberg system, however, is that cars move around requiring a plurality of master clocks with competing radio frequency links. Providing a large number of these master clocks with radio frequency transmitters entails a considerable infrastructure cost. Moreover, the spectrum for radio frequency communications is highly regulated by agencies such as the Federal Communication Commission, and there is little legal spectrum space available for such applications.
Therefore, there is a need for improving the accuracy of automobile clocks and reducing the necessity to use the cumbersome manual interfaces for updating the current time, especially due to changes in the time zone and prevailing time. Preferably, a solution should not require expensive investments in infrastructure or encounter regulatory difficulties.